Almansouri Taghreed, Waller Rachel, Wharton Stephen B, Heath Paul R, Matthews Fiona E, Brayne Carol, van Eeden Fredericus, Simpson Julie E
Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK.
Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
Int J Mol Sci. 2024 Apr 18;25(8):4445. doi: 10.3390/ijms25084445.
Age-associated deep-subcortical white matter lesions (DSCLs) are an independent risk factor for dementia, displaying high levels of CD68 microglia. This study aimed to characterize the transcriptomic profile of microglia in DSCLs and surrounding radiologically normal-appearing white matter (NAWM) compared to non-lesional control white matter. CD68 microglia were isolated from white matter groups ( = 4 cases per group) from the Cognitive Function and Ageing Study neuropathology cohort using immuno-laser capture microdissection. Microarray gene expression profiling, but not RNA-sequencing, was found to be compatible with immuno-LCM-ed post-mortem material in the CFAS cohort and identified significantly differentially expressed genes (DEGs). Functional grouping and pathway analysis were assessed using the Database for Annotation Visualization and Integrated Discovery (DAVID) software, and immunohistochemistry was performed to validate gene expression changes at the protein level. Transcriptomic profiling of microglia in DSCLs compared to non-lesional control white matter identified 181 significant DEGs (93 upregulated and 88 downregulated). Functional clustering analysis in DAVID revealed dysregulation of haptoglobin-haemoglobin binding (Enrichment score 2.5, = 0.017), confirmed using CD163 immunostaining, suggesting a neuroprotective microglial response to blood-brain barrier dysfunction in DSCLs. In NAWM versus control white matter, microglia exhibited 347 DEGs (209 upregulated, 138 downregulated), with significant dysregulation of protein de-ubiquitination (Enrichment score 5.14, < 0.001), implying an inability to maintain protein homeostasis in NAWM that may contribute to lesion spread. These findings enhance understanding of microglial transcriptomic changes in ageing white matter pathology, highlighting a neuroprotective adaptation in DSCLs microglia and a potentially lesion-promoting phenotype in NAWM microglia.
与年龄相关的深部皮质下白质病变（DSCLs）是痴呆的独立危险因素，其小胶质细胞中CD68水平较高。本研究旨在描绘DSCLs及其周围放射学上看似正常的白质（NAWM）中小胶质细胞的转录组图谱，并与非病变对照白质进行比较。使用免疫激光捕获显微切割技术从认知功能与衰老研究神经病理学队列的白质组（每组 = 4例）中分离出CD68小胶质细胞。发现微阵列基因表达谱（而非RNA测序）与CFAS队列中经免疫激光捕获显微切割的尸检材料兼容，并鉴定出显著差异表达基因（DEGs）。使用注释、可视化和综合发现数据库（DAVID）软件进行功能分组和通路分析，并进行免疫组织化学以在蛋白质水平验证基因表达变化。与非病变对照白质相比，DSCLs中小胶质细胞的转录组分析确定了181个显著的DEGs（93个上调，88个下调）。DAVID中的功能聚类分析显示触珠蛋白-血红蛋白结合失调（富集分数2.5， = 0.017），通过CD163免疫染色得到证实，表明DSCLs中小胶质细胞对血脑屏障功能障碍有神经保护反应。在NAWM与对照白质的比较中，小胶质细胞表现出347个DEGs（209个上调，138个下调），蛋白质去泛素化显著失调（富集分数5.14， < 0.001），这意味着NAWM中无法维持蛋白质稳态，可能导致病变扩散。这些发现增进了对衰老白质病理学中小胶质细胞转录组变化的理解，突出了DSCLs中小胶质细胞的神经保护适应性以及NAWM中小胶质细胞潜在的促病变表型。
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